Av data reproducing device, method for reproducing av data, and recording medium for the same

ABSTRACT

An original stream file and an after-recording data file are managed as different files. In the original stream file, data is made up of sets of partial data (CU) divided in accordance with a predetermined interval. Likewise, in the after-recording data file, data is made up of sets of partial data (CA) divided in accordance with a predetermined interval. These sets of data are recorded onto a disc such that the after-recorded data (CA) is recorded in a region adjacent to a relevant original stream (CU). This allows reproduction and real-time after-recording with the use of a general MPEG-2 PS/TS decoder. Moreover, this allows realization of data recording that causes less interruption of reproduction when non-destructive editing is carried out with respect to an after-recorded result.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of copending application U.S. Ser.No. 10/531,534, filed on Apr. 15, 2005, which is a National Phaseapplication filed under 35 USC 371 of PCT International Application No.PCT/JP03/13209, filed on Oct. 15, 2003, which claims priority under 35USC 119 to Japanese Application No. 2002-303648, filed on Oct. 17, 2002,and Japanese Application No. 2003-005058, filed on Jan. 10, 2003, all ofwhich are incorporated herein in their entireties.

TECHNICAL FIELD

The present invention relates to (i) a method for recording image dataand audio data onto a random accessible recording medium such as a harddisk, an optical disc, and a semiconductor memory; to (ii) a recordingapparatus; and to (iii) a recording medium.

BACKGROUND ART

A video digital recording/reproducing apparatus (hereinafter, referredto as “video disc recorder”) using a disc medium has begun to bepervasive. Required is a technique for realizing, at an inexpensiveprice, an after-recording function in such a video disc recorder, as isthe case with a tape medium. The after-recording function refers to atechnique for further adding information, especially audio information,to recorded audio information and/or recorded video information.

A conventional technique for realizing such an after-recording functionusing a disc medium was provided by the present inventors, and isdisclosed in Japanese Laid-Open Patent Publication Tokukai 2001-43616(published on Feb. 16, 2001). The following briefly explains thistechnique with reference to FIG. 20( a) and FIG. 20( b).

In Japanese Laid-Open Patent Publication Tokukai 2001-43616, a streamfile 3000 is in compliance with a unique stream format, and is sostructured that regions for storing the after-recorded data are insertedamong original stream data (initially recorded video/audio data) dividedat a predetermined reproduction time interval. The after-recorded datais reproduced in synchronism with the original stream data. For example,FIG. 20( a) illustrates that an after-recording data region 3011 forstoring after-recorded audio data that is to be reproduced insynchronism is inserted just before partial original stream data 3021.Likewise, after-recording data regions 3012 and 3013 are inserted justbefore partial original stream data 3022 and 3023, respectively.

The stream file 3000 is recorded onto an optical disc 3001 such thateach set of partial original stream data and each after-recording dataregion are disposed physically adjacent to each other as shown in FIG.20( b). This minimizes seeking operation during the synchronousreproduction of the partial original stream data and the after-recordeddata, and restrains interruption of the reproduction due to the seekingoperation. Further, a real-time after-recording is ensured by settingreproduction time of the partial original stream data to such a value(roughly several seconds) that allows for the real-time after-recordingand that is determined in consideration of a seeking time.

Incidentally, examples of widely used data recording method are:Transport Stream (hereinafter, referred to as “MPEG-2 TS”) and ProgramStream (hereinafter, referred to as “MPEG-2 PS”), each of which has adifferent structure from the stream structure described in JapaneseLaid-Open Patent Publication Tokukai 2001-43616, and each of which isdefined by ISO/IEC 13818-1. For example, MPEG-2 PS is used forDVD-Video, and MPEG-2 TS is used for a data transfer format betweendevices by way of digital broadcasting or the IEEE-1394. Conventionalafter-recording techniques in consideration of MPEG-2 PS/TS aredescribed in Japanese Laid-Open Patent Publication Tokukai 2000-306327(published on Nov. 2, 2000), and Japanese Laid-Open Patent PublicationTokukaihei 11-298845/1999 (published on Oct. 29, 1999).

However, in cases where the stream structure described in JapaneseLaid-Open Patent Publication Tokukai 2001-43616 is applied to MPEG-2PS/TS, a general decoder possibly cannot normally carry out decoding forreproduction. A reason for this is explained as follows.

It is determined in MPEG-2 TS/PS that video data and audio data aremultiplexed such that no underflow and no overflow occur in respectivebuffer memories of an audio decoder and a video decoder that are incompliance with a decoder model set as a standard (reference). However,in the stream structure of Japanese Laid-Open Patent Publication Tokukai2001-43616, audio data corresponding to one second or longer is storedin each of the after-recording data regions. When such a stream file isreproduced by using a general MPEG-2 TS/PS decoder, the MPEG-2 TS/PSdecoder receives, at a time, the audio data corresponding to one secondor longer. This causes overflow of the buffer memory of the audiodecoder.

Further, according to the after-recording function described in JapaneseLaid-Open Patent Publication Tokukai 2000-306327, the after-recordingdata region is multiplexed in the stream in accordance with theaforementioned MPEG-2 PS multiplexing rule; however, the after-recordingfunction suffers from a difficulty in the real-time after-recording whena transfer rate to or from a disc is low.

On the other hand, in Japanese Laid-Open Patent Publication Tokukaihei11-298845/1999, the after-recorded data and the original stream data arerecorded onto different files such that each of the files is incompliance with the MPEG-2 PS multiplexing rule. In this case, a filecontaining the after-recorded data and a file containing the originalstream data are alternately read out, so that a seeking operation isrequired to be repeated during the reproduction of the after-recordedresult. For this reason, when a non-destructive editing is carried outwith respect to the after-recorded result, the seeking operation is morelikely to cause interruption of reproduction especially between scenes.The non-destructive editing refers to an editing that is virtuallycarried out by using reproduction route information instead of using thestream data on a disc. Moreover, the technique is also disadvantageousin power consumption.

The present invention is made in light of the problem, and its object isto provide a data recording method that allows reproduction andreal-time after-recording in a general MPEG-2 PS/TS decoder, and allowsless interruption of reproduction when a non-destructive edit is carriedout with respect to an after-recorded result.

DISCLOSURE OF INVENTION

A method, of the present invention, for recording, onto a recordingmedium, (i) AV data obtained by multiplexing a plurality of sets ofstream data in accordance with a predetermined multiplexing rule, and(ii) associated data to be reproduced in synchronism with the AV data,the method includes: (a) a first step of dividing the AV data intopartial AV data and of dividing the associated data into partialassociated data, in accordance with a predetermined interval; (b) asecond step of securing, in the recording medium, a first continuousregion for continuously storing a series of the partial AV data and thepartial associated data; (c) a third step of continuously recording thepartial AV data and the partial associated data onto the firstcontinuous region; and (d) a fourth step of recording, onto therecording medium, file system management information for (i) managingthe partial AV data and the partial associated data as different files,and (ii) managing information for handling the partial AV data and thepartial associated data as the different files.

With the arrangement, the AV data (e.g., original stream) and theassociated data (e.g., after-recorded data), which are to be recordedonto the recording medium, are respectively divided into the sets of thepartial AV and the partial associated data by performing the first step.With this, the partial AV data and the partial associated data have suchscales (lengths) that ensure the seamless reproduction and the real-timeafter-recording, respectively.

The partial AV data and the partial associated data thus obtained by thedividing are reproduced in synchronism with each other, and the partialAV data and the partial associated data are continuously recorded byperforming the second step and the third step such that they arephysically adjacent to each other.

Further, the file system management information recorded in the fourthstep manages the partial AV data and the partial associated data asdifferent files. This ensures the real-time after-recording, and allowsreproduction with the use of a general MPEG-2 PS decoder whosenon-destructive editing property is excellent. Because the partial AVdata and the partial associated data are positioned adjacent to eachother, the seeking occurs less frequently when the AV data and theassociated data are reproduced in synchronism. That is, this providesmargin for further synchronized reproduction with other data. Forexample, the reproduction is less likely to be interrupted even whengraphics data is added as well as the after-recorded audio data by wayof the non-destructive editing.

The file system management information managing the partial AV data andthe partial associated data as different files has the informationindicating the correspondence relation between the partial AV data andthe partial associated data, which are positioned adjacent to each otherin the recording medium. By recording the information indicating thecorrespondence relation, it is possible to easily recognize respectivepositions of the continuously stored partial AV data and partialassociated data even when the file system management information is notreferred. This optimizes the data readout.

The method of the present invention may further include: a fifth step ofrecording, onto the recording medium, (i) reproduction start time of thepartial AV data, and (ii) correspondence information of the partial AVdata and the partial associated data, both of which are disposed in thefirst continuous region.

The arrangement allows easy specification of the position of the partialassociated data (after-recording region) corresponding to the partial AVdata to be after-recorded.

The method of the present invention may further include: a sixth step ofrecording, onto the recording medium, information indicating whether ornot the partial associated data is recorded adjacent to thecorresponding partial AV data.

In cases where defect occurs during the recording of the partial AV dataand the partial associated data, the partial associated data beingrecorded is possibly discarded and the CA is newly recorded onto anotherregion.

To accommodate to such a case, the information managing the partialassociated data indicates that no partial associated data is positionedadjacent to the relevant AV data. Therefore, it is possible to easilyrecognize parts in which the partial AV data and the partial associateddata are not continuously recorded, during the non-destructive editingor reproduction of the non-destructively edited result. With this, theuser can be notified in advance that the reproduction will be likely tobe interrupted during the reproduction of the parts.

Another method for recording, onto a recording medium, (i) AV dataobtained by multiplexing a plurality of sets of stream data inaccordance with a predetermined multiplexing rule, and (ii) associateddata to be reproduced in synchronism with the AV data, the methodincludes: (a) a seventh step of dividing the AV data into partial AVdata in accordance with a predetermined interval; (b) an eighth step ofsecuring, in the recording medium, a first continuous region forcontinuously storing (i) a series of the partial AV data and (ii)partial reservation data for securing, during recording of theassociated data, a region for storing partial associated data that is sodivided as to correspond to the partial AV data; (c) a ninth step ofcontinuously recording the partial AV data and the partial reservationdata onto the first continuous region, while making sets of the partialreservation data; and (d) a tenth step of recording, onto the recordingmedium, file system management information for (i) managing the partialAV data and the partial reservation data as different files, and (ii)managing information for handling the partial AV data and the partialreservation data as different files.

With the arrangement, the AV data (e.g., original stream) to be recordedonto the recording medium is divided into partial AV data by performingthe seventh step such that the partial AV data has a length (scale) thatensures the seamless reproduction and the real-time after-recording.

The partial AV data thus obtained by the dividing and the partialreservation data are continuously recorded by performing the eighth stepand the ninth step such that they are physically positioned adjacent toeach other. The partial reservation data secures the region for storingthe partial associated data that is to be reproduced in synchronism withthe partial AV data.

Further, the file system management information recorded in the tenthstep manages the partial AV data and the partial associated data asdifferent files. This ensures the real-time after-recording during therecording of the associated data, and allows reproduction with the useof a general MPEG-2 PS decoder whose non-destructive editing property isexcellent.

The method may further include: (a) a eleventh step of dividing, duringthe recording of the associated data, the associated data into partialassociated data in accordance with a predetermined interval; (b) atwelfth step of recording, during the recording of the associated data,the partial associated data onto the region secured by the partialreservation data which is stored in continuity with the partial AV datacorresponding to the associated data; (c) a thirteenth step ofrecording, onto the recording medium during the recording of theassociated data, file system management information for (i) managing thepartial associated data as a different file from the respective files ofthe partial AV data and the partial reservation data, (ii) managinginformation for handling the partial associated data as a differentfile.

With the arrangement, the partial AV data and the partial associateddata are positioned adjacent to each other, so that the seeking occursless frequently when the AV data and the associated data are reproducedin synchronism. That is, this provides margin for further synchronizedreproduction with other data. For example, the reproduction is lesslikely to be interrupted even when graphics data is added as well as theafter-recorded audio data by way of the non-destructive editing.

The file system management information managing the partial AV data andthe partial associated data as different files has the informationindicating the correspondence relation between the partial AV data andthe partial associated data, which are positioned adjacent to each otherin the recording medium. By recording the information indicating thecorrespondence relation, it is possible to easily recognize respectivepositions of the continuously stored partial AV data and partialassociated data even when no reference to the file system managementinformation is made. This optimizes the data readout.

Additional objects, features, and strengths of the present inventionwill be made clear by the description below. Further, the advantages ofthe present invention will be evident from the following explanation inreference to the drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1( a) and FIG. 1( b) illustrates an embodiment of the presentinvention. FIG. 1( a) illustrates respective data structures of anoriginal stream file and an after-recording data file. FIG. 1( b)illustrates respective positions, in a disc, of data of the originalstream file and the after-recording data file.

FIG. 2 is a block diagram schematically illustrating a structure of avideo disc recorder according to embodiments of the present invention.

FIG. 3( a) illustrates a directory/file structure. FIG. 3( b)illustrates relation among sets of management information of thedirectory/file structure in the UDF.

FIG. 4 illustrates a file/directory structure in Embodiment 1 of thepresent invention.

FIG. 5( a) through FIG. 5( c) each illustrate a structure of an originalstream file in Embodiment 1 of the present invention.

FIG. 6 is an explanatory diagram illustrating a structure of anafter-recording data file in Embodiment 1 of the present invention.

FIG. 7 illustrates a reference device model in Embodiment 1 of thepresent invention.

FIG. 8 illustrates a reference after-recording algorism in Embodiment 1of the present invention.

FIG. 9 illustrates a structure of a stream management information filein Embodiment 1 of the present invention.

FIG. 10( a) and FIG. 10( b) each illustrate a structure ofvideo_unit_table in Embodiment 1 of the present invention.

FIG. 11( a) and FIG. 11( b) each illustrate a structure of VU_flags inEmbodiment 1 of the present invention.

FIG. 12( a) and FIG. 12( b) each illustrate a structure ofcontinuous_area_table in Embodiment 1 of the present invention.

FIG. 13( a) and FIG. 13( b) illustrate a structure of CA_flags inEmbodiment 1 of the present invention.

FIG. 14 illustrates a structure of a program information file inEmbodiment 1 of the present invention.

FIG. 15( a) and FIG. 15( b) illustrate a structure of scene_table inEmbodiment 1 of the present invention.

FIG. 16 is a flowchart illustrating a flow of recording processes inEmbodiment 1 of the present invention.

FIG. 17 is a flowchart illustrating a flow of reproduction processes inEmbodiment 1 of the present invention.

FIG. 18 is a flowchart illustrating a flow of scene reproductionprocesses in Embodiment 1 of the present invention.

FIG. 19( a) and FIG. 19( b) illustrate another embodiment of the presentinvention. FIG. 19( a) illustrates respective data structures of twokinds of stream files in Embodiment 2 of the present invention. FIG. 19(b) illustrates how respective data in the stream files is positioned ina disc.

FIG. 20( a) and FIG. 20( b) illustrate a conventional technique. FIG.20( a) illustrates a data structure of a stream file. FIG. 20( b)illustrates how data in the stream file is positioned in a disc.

FIG. 21 illustrates a file/directory structure in Embodiment 3 of thepresent invention.

FIG. 22( a) and FIG. 22( b) illustrate one embodiment of the presentinvention. FIG. 22( a) illustrates respective data structures of anoriginal stream file and an after-recording region reservation file inEmbodiment 3 of the present invention. FIG. 22( b) illustrates howrespective data of the original stream file and the after-recordingregion reservation file are positioned in the disc just after picturerecording.

FIG. 23( a) illustrates respective data structures of a graphics fileand an after-recording data file in Embodiment 3 of the presentinvention. FIG. 23( b) illustrates how the graphics file, theafter-recording data file, and the original stream file, and theafter-recording region reservation file are positioned in the disc justafter the after-recording and non-destructive editing.

FIG. 24 illustrates a structure of a program information file inEmbodiment 3 of the present invention.

FIG. 25( a) and FIG. 25( b) illustrate subaudio_table in Embodiment 3 ofthe present invention.

FIG. 26( a) and FIG. 26( b) illustrate graphics_table in Embodiment 3 ofthe present invention.

FIG. 27( a) and FIG. 27( b) illustrate SA_flags and gr_flags inEmbodiment 3 of the present invention.

FIG. 28 is a flowchart illustrating a flow of a scene reproductionprocesses in Embodiment 3 of the present invention.

FIG. 29( a) and FIG. 29( b) illustrate one embodiment of the presentinvention. FIG. 29( a) illustrates respective data structures of anoriginal stream file and an after-recording data file in Embodiment 4 ofthe present invention. FIG. 29( b) illustrates how respective data inthe original stream file and the after-recording data file arepositioned in the disc.

FIGS. 30( a) and 30(b) illustrate a reference after-recording algorismin Embodiment 4 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description deals with detailed description of Embodimentsof the present invention with reference to figures. Firstly explainedhere is a structure commonly used in the present invention, andsubsequently explained are unique things in respective Embodiments. Notethat the present invention is not limited to these.

<System Structure>

FIG. 2 is a block diagram illustrating a basic system of a video discrecorder that is common in Embodiments described below.

As shown in FIG. 2, the video disc recorder includes: a bus 100, a hostCPU 101, a RAM 102, a ROM 103, a user interface 104, a system clock 105,an optical disc 106, a pickup 107, an ECC (Error Correcting Coding)decoder 108, an ECC encoder 109, an audio reproduction buffer 110, avideo reproduction buffer 111, a de-multiplexer 112, a multiplexer 113,a recording buffer 114, an audio decoder 115, a video decoder 116, anaudio encoder 117, a video encoder 118, an audio recording buffer 119, avideo recording buffer 120, a de-multiplexer 121, an after-recordingdata reproduction buffer 122, a dividing processing section 123 (meansfor dividing into AV data and partial associated data), a vacant regionmanagement section 125 (means for securing a continuous region), amanagement information processing section 126, a camera (not shown), amicrophone (not shown), a speaker (not shown), a display (not shown),and the like. The pickup 107, the ECC decoder 108, and the ECC encoder109 constitute a drive 127 (means for continuously recording partial AVdata and the partial associated data; means for recording file systemmanagement information onto the recording medium).

The host CPU 101 controls, via the bus 100, the de-multiplexer 112, themultiplexer 113, the pickup 107, the audio decoder 115, the videodecoder 116, the audio encoder 117, and the video encoder 118.

During reproduction, data read out from the optical disc 106 via thepickup 107 is subjected to an error correction carried out by the ECCdecoder 108. In the data thus subjected to the error correction, filesystem management information is processed by the management informationprocessing section 126. Then, the data is sent to the de-multiplexer 112or de-multiplexer 121.

According to an instruction from the host CPU 101, the de-multiplexer112 sends audio data of the readout data to the audio reproductionbuffer 110, and sends video data thereof to the video reproductionbuffer 111. Likewise, the de-multiplexer 121 sends the readout data tothe after-recording data reproduction buffer 122 in accordance with aninstruction from the host CPU 101.

The audio decoder 115 reads out the data from the audio reproductionbuffer 110 and the after-recording data reproduction buffer 122, andcarries out decoding with respect to the readout data, in accordancewith an instruction from the host CPU 101. Likewise, the video decoder116 reads out the data from the video reproduction buffer 111, andcarries out decoding with respect to the readout data, in accordancewith an instruction from the host CPU 101.

On the other hand, during recording, data compressed and encoded by theaudio encoder 117 is sent to the audio recording buffer 119, and datacompressed and encoded by the video encoder 118 is sent to the videorecording buffer 120. According to an instruction from the host CPU 101,the multiplexer 113 reads out the respective data from the audiorecording buffer 119 and the video recording buffer 120, and carries outAV-multiplexing with respect to the readout data, and sends theAV-multiplexed data to the dividing processing section 123. The dividingprocessing section 123 divides the AV-multiplexed data at everypredetermined interval, and sends the divided data to the recordingbuffer 114. On this occasion, the vacant region management section 125secures a continuous region for the recording of the data, and the ECCencoder 109 adds an error correction code to the AV-multiplexed dataread out from the recording buffer 114, and the pickup 107 records thedata onto the secured continuous region in the optical disc 106.

An encoding format of the audio data is MPEG-1 Layer-II defined byISO/IEC 13818-3, and an encoding format of the video data is MPEG-2defined by ISO/IEC13818-2. The optical disc 106 is a re-writable opticaldisc, such as DVD-RAM, in which 2048 byte is handled as one sector andin which 16 sectors constitute an ECC block for the sake of the errorcorrection.

<File System>

The following explains a UDF (Universal Disk Format) adopted as a formatof a file system used in the description of the present invention, withreference to FIG. 3( a) and FIG. 3( b). FIG. 3( a) illustrates adirectory/file structure, and FIG. 3( b) illustrates an example in whichthe directory/file structure is recorded in compliance with the UDF.

An AVDP (Anchor Volume Descriptor Pointer) 602 shown in FIG. 3( b)corresponds to an entry point for a search for management information ofthe UDF, and is usually recorded in a 256-th sector, an N-th sector, oran (N-256)-th sector (N refers to a maximum logical sector number). AVDS (Volume Descriptor Sequence) 601 stores management information abouta volume. The volume is a region managed by the UDF, and one volumegenerally exists in one disc, and generally includes one partition. OneFSD (File Set Descriptor) 603 exists in the partition. Positioninformation in the partition is indicated by a logic block number thatcorresponds to a sector number counted from top of the partition. Notethat one logic block corresponds to one sector. Note also that eachpartition (not shown) includes a table indicating whether or not a logicblock termed “space bitmap” has been allocated to each file.

The FSD 603 includes position information of an FE 604 serving as a fileentry (FE) of a root directory. The position information is referred toas “extent” including logic block numbers and the number of the logicblocks. The FE manages an aggregate of the extents. By rewriting,adding, and/or deleting each extent, it is possible for the FE to changeorder of sets of actual data constituting the file, and/or to carry outdata insertion and data deletion.

The FE 604 manages a region 605 storing an aggregate of file identifierdescriptors (FIDs), each of which stores name(s) of a file and/or adirectory just below the root directory. An FID 611 and an FID 612 inthe region 605 include position information of FE 606 and FE 608,respectively. The FE 606 manages a filename of a file 621 and anaggregation of extents thereof, and the FE 608 manages a filename of afile 622 and an aggregation of extents thereof. Specifically, the FE 606manages, as the extents, a region 607 and a region 610, each of which isa region constituting the actual data of the file 621. An access to theactual data of the file 621 can be made by following the links in orderof the AVDP 602, the VDS 601, the FSD 603, the FE 604, the FID 611, theFE 606, the region 607, and the region 610.

Embodiment 1

Embodiment 1 of the present invention will be explained below withreference to FIG. 1, and FIG. 4 through FIG. 18.

<File/Directory Structure>

A file/directory structure according to Embodiment 1 is explained withreference to FIG. 4. As shown in FIG. 4, data of Embodiment 1 is storedin five types of files.

An original stream file (SHRP0001.M2P) is a file prepared per picturerecording, and is in compliance with the MPEG-2 PS (Program Stream)format. An after-recording data file (SHRP0001.PRE) is a file for (i)securing a region for after-recording, and (ii) storing after-recordeddata. An original stream management information file (SHRP0001.OMI) is afile for storing (i) time-address correspondence information about theoriginal stream file; (ii) attribution information about the originalstream file; (iii) attribution information about the after-recordingdata file; and (iv) information indicative of a correspondencecorrelation with the original stream file. The original streammanagement information file is provided per original stream file. Aprogram information file (SHRP0001.PGM) is a file for storinginformation that specifies which parts in the stream or the data are tobe reproduced and that specifies order of reproducing these parts. Notethat the program corresponds to one of contents, and is a target to bereproduced in response to user's instruction.

The four files above are newly prepared during a picture recording. Thefiles have different extensions, but are arranged so that others are incommon than the extensions for the purpose of clarifying a relationamong the files. During audio after-recording, after-recorded audio datais overwritten in a predetermined location of the after-recording datafile, and the after-recording data management information file reflectsthe overwriting. Moreover, the program information file is also changedso that the added after-recorded audio data is also a target to bereproduced.

During the non-destructive editing, the program information file isnewly prepared, and stores one by one (i) filenames of the originalstream management information file and/or the after-recording datamanagement information file, each of which manages the data to bereproduced; and (ii) the parts of the data which the user wishes toreproduce. Note that respective data structures of the files will beexplained later.

<A structure of an AV Stream>

The following description explains a structure of an AV stream inEmbodiment 1 with reference to FIG. 5.

Firstly, the original stream file is explained with reference to FIG. 5.Content of the original stream file is in compliance with the MPEG-2 PSformat, and is constituted by the integral number of continuous units(CUs) as shown in FIG. 5( a). Each CU is a recording unit by which therecording is carried out with respect to a disc. Length of the CU is soset as to ensure (i) seamless reproduction (reproduction during which animage and a sound are never interrupted) and (ii) real-timeafter-recording (audio recording carried out during a seamlessreproduction of video to be subjected to the after-recording),irrespective of how the CUs constituting the AV stream are provided onthe disc. A method for setting the length will be described later.

Each CU is constituted by the integral number of video units (VUs) asshown in FIG. 5( b). Each VU is a individually reproducible unit, andcan be an entry point during a reproduction. The VU is constituted bythe integral number of audio packs (A#1 through A#K) and video packs(V#1 through V#L). The audio packs and the video packs are soAV-multiplexed as to maintain an MPEG-2 PS compatible decoder model. Asize of each pack is as large as a sector size such that excess data isnot read out during readout of the disc. Note that the video data to bepacked is constituted by one or two GOPs (Groups of picture). Note alsothat the audio data to be packed is constituted by the integral numberof AAUs (Audio Access Units).

Note that the GOP is a unit of image compression of the MPEG-2 videostandard, and is constituted by a plurality of video frames (typically,15 frames or so). The AAU is a unit of audio compression of the MPEG-1Layer-II standard, and is constituted by 1152 sound waveform samplepoints. In cases where a sampling frequency is 48 kHz, reproduction timeper AAU is 0.024 second. Further, a sequence header (SH) is provided ata head of video data in each VU such that individual reproductions arecarried out in the VU unit.

Note that a VU at the end of the CU is padded by a pack storing apadding packet such that the CU is constituted by the integral number ofECC blocks.

<After-Recording Data File>

The following explains a structure of the after-recording data file withreference to FIG. 6. As shown in FIG. 6, the after-recording data fileis constituted by the integral number of continuous areas (CAs). One CAcorresponds to one CU in the original stream file, and storesafter-recording data corresponding to the reproduction data of thecorresponding CU. For example, a CA#n stores after-recording audio datathat is to be reproduced in synchronization with a CU#n of the originalstream file. The CA is constituted by the integral number of ECCblock(s).

The after-recording data file is in compliance with the MPEG-2 PS formatas the original stream file is. During initial picture recording,padding packets are recorded onto the after-recording data file. Afterthe after-recording, packs containing the after-recorded data areoverwritten in the after-recording data file. The packs to beoverwritten have SCRs (System Clock References) in pack headers and havePTSs (Presentation Time Stamps) in packet headers, respectively. TheSCRs and the PTSs suit to SCRs and PTSs of the corresponding audio packsin the original stream file, respectively. With this, the audio data ofthe original stream can be easily replaced with the after-recorded databy overwriting the audio packs of the CU with the corresponding audiopacks of the CA.

<Layout in the Disc>

The following description explains how respective data of the originalstream file and the after-recording data file are disposed in the discwith reference to FIGS. 1( a) and (b). FIG. 1( a) illustrates theoriginal stream file (SHRP0001.M2P) and the after-recording data file(SHRP0001.PRE), which correspond to each other. The original stream fileand the after-recording data file are recorded onto the optical disc 106such that the CAs come just before the corresponding CUs, respectively(see FIG. 1( b)).

With this, the data (each CA and each CU) to be reproduced insynchronism are positioned adjacent to each other on the disc. Thisminimizes a movement of the pickup during reproduction. Accordingly, theinterruption is less likely to occur during reproduction of anon-destructively edited result as described below. Because such a smallCA in size is so positioned as to be read out prior to the CU, lessbuffer memory amount can be used for the synchronized reproduction.

<Method for Determining a CU Scale>

A method for determining reproduction time of the CU will be explainedwith reference to FIG. 7 and FIG. 8. In the method, the reproductiontime of the CU is determined such that the seamless reproduction ismaintained when the after-recording is carried out by using, for sake ofensuring compatibility between devices, (i) a reference device(reference device model); and (ii) a reference after-recording algorism.

Firstly explained is the reference device model with reference to FIG.7. The reference device model is made up of a pickup (not shown); an ECCencoder/decoder 501 connected to the pickup; a track buffer 502; ade-multiplexer 503; an after-recording buffer 504; an audio encoder 509;a video buffer 505; an audio buffer 506; a video decoder 507; and anaudio decoder 508.

Because the reference device model has the single pickup, readout ofreproduction data from a disc 500 and recording of after-recorded dataonto the disc 500 are carried out in a time-sharing manner. Thereproduction data is read out from the disc 500 together with the CA. AnECC block (CA block) including the readout CA is sent from the trackbuffer 502 to the after-recording buffer 504.

The audio encoder 509 sends the after-recorded data to theafter-recording buffer 504 in a cycle of the AUU. The output data isoverwritten in the corresponding CA block in the after-recording buffer504. The CA block is recorded onto a predetermined ECC block, with theresult that the after-recorded data is recorded.

Here, it is assumed that Rs indicates both (i) a transmission speed ofthe audio frame data to the ECC encoder 501, and (ii) a transmissionspeed of the audio frame data from the ECC decoder 501. It is furtherassumed that Ta indicates a maximum period during which the readout andthe recording are suspended via an access. Note that the period Taincludes seeking time, rotation latency time, and time required forcompleting of outputting, from the ECC decoder 501, of the datainitially read out after the access. Embodiment 1 assumes that Rs is 20Mbps and Ta is one second.

Next, the reference after-recording algorithm will be explained withreference to FIG. 8. Note that numbers {circle around (1)} to {circlearound (6)} in FIG. 8 respectively correspond to the following numbers{circle around (1)} to {circle around (6)} which describe the algorithmbriefly as follows:

{circle around (1)} Read out data for reproduction.{circle around (2)} Make an access to a CA(N), which is an n-th CA,concurrently with completion of encoding of audio data that correspondsto the CA(N).{circle around (3)} Recording the CA(N) onto the disc.{circle around (4)} Go back to the readout position where the pickupwas.{circle around (5)} Read out the data for reproduction.{circle around (6)} Make an access to a CA(N+1), which is an (n+1)-thCA, concurrently with completion of encoding of audio data thatcorresponds to the CA(N+1).After that, operations {circle around (3)} through {circle around (6)}are repeated.

The after-recording, using the reference after-recording algorithm inthe reference device model, ensures that the after-recording buffer 504is free from overflow and that the track buffer 502 is free fromunderflow, as long as the following condition is satisfied:

Te(i)≧Tr(i)+Tw(i)  (1)

where Te(i) indicates maximum reproduction time of a CU#i that is anarbitrary CU in the AV stream; Tr(i) indicates maximum readout timeincluding a division jump; and Tw(i) indicates maximum time forrecording a CA#i that corresponds to the CU#.

This is because Formula (1) satisfies a sufficient condition of theseamless reproduction. The condition is represented by the followingFormula (2):

$\begin{matrix}{\sum\limits_{i}\; {{{Te}\left( {\geqq i} \right)}{\sum\limits_{i}\; \left( {{{Tr}(i)} + {iT}} \right.}}} & (2)\end{matrix}$

where Ta indicates maximum round-trip time for the pickup to go to andreturn from the CA in the disc.

Because the after-recorded data is recorded onto the disc insynchronization with the completion of the encoding of the CA, datanever keeps being accumulated in the after-recording buffer 504 and theafter-recording buffer 504 is therefore free from the overflow.

Tr(i) in Formula (1) satisfies the following Formula (3):

Tr(i)=Te(i)×Ro/Rs+Te(i)×Ra/Rs+Ta  (3)

where Ro indicates maximum bit rate of the original stream, Ra indicatesmaximum bit rate of the after-recording audio stream, and Rs indicatesinput speed and output speed of the audio frame data, i.e., indicatesaudio bit rate.

A first term in a right side of Formula (3) indicates time for readingout a VU in a CU, and a second term therein indicates time for readingout the CA, and a third term therein indicates time for an access madeby the division jump associated with the readouts. The division jump iscarried out once at the maximum during the readout of the CU, so thatFormula (3), i.e., Tr(i) indicates time corresponding to one accessoperation.

Tw(i) satisfies the following Formula (4):

Tw(i)=2Ta+Te(i)×Ra/RS  (4)

Here, a first term in a right side of Formula (4) indicates access time(forward-backward access time) for the pickup to go to and come backfrom the CA. The maximum access time Ta is used to represent theforward-backward access time because each CA can be recorded onto anyposition in the disc. Specifically, there is such a possibility that aCU which is being read out is positioned in an innermost side of thedisc, and that a CA to be recorded is positioned in an outermost side ofthe disc. For this reason, the forward-backward access time is requiredto be estimated at the maximum value.

Note that the CA is recorded continuously onto the disc as describedabove, so that no access is made during the recording of the CA. Thisshortens time required for the recording of the CA, with the result thata lower limit value of the reproduction time of the CU can be restrainedto be low.

When Formula (3) and Formula (4) are substituted in Formula (1) to solvefor Te(i), a condition of Te(i) that ensures the real-timeafter-recording can be obtained as the following Formula (5):

Te(i)≧(3Ta×Rs)/(Rs−Ro−2Ra)  (5)

Indicated by Rv is input speed and output speed of the video frame data,i.e., is video bit rate.

Accordingly, the CU reproduction time lower limit value Temin thatensures the after-recording is represented by the following formula (6):

Temin=(3Ta×Rs)/(Rs−Ro−2Ra)  (6)

A CU reproduction time upper limit value Temax is so set as to satisfythe following Formula (7):

Temax=(3Ta×Rs)/(Rs−Ro−2Ra)+Tvmax  (7)

where Tvmax indicates maximum reproduction time of the VU.

The setting of the upper limitation value of the CU reproduction time iscarried out so as to allow for estimation of maximum amount of theretardation memory required for the synchronized reproduction of theafter-recorded audio and the normal audio, and so as to ensurereproduction compatibility. Note that, in Embodiment 1, the multiplexinginterval lower limit value Temin is set according to the audio bit rateRa and the video bit rate Rv; however, the lower limit value may beconstant at any value as long as the lower limit value is based onmaximum bit rate.

Moreover, reproduction time of the VU in the stream may be constant orvariable as long as the reproduction time of the CU meets theaforementioned restriction.

Further, Embodiment 1 assumes that the division jump and the movement ofthe pickup to a previous CU are asynchronously carried out. A reason forthis is as follows. That is, a condition for the real-timeafter-recording is stricter (the readout of the reproduction data isinterrupted for a longer period of time) in cases where the divisionjump and the movement are asynchronously carried out, as compared withcases where the division jump and the movement are synchronously carriedout. In other words, in cases where the real-time recording is attainedwhen the division jump and the movement are asynchronously carried out,the real-time recording is accordingly attained when the division jumpand the movement are synchronously carried out. This allows an increasein freedom of implementation of the present invention.

Therefore, Temin may be set on an assumption that the division jump andthe movement of the pickup to the previous CU are carried out insynchronism. In this case, the second term in the right side of Formula3 is omitted.

<Formats of Management Information Files>

The following description explains management information file formatsaccording to the present invention with reference to FIG. 9 through FIG.15.

Firstly explained is the original stream management information file. Asshown in FIG. 9, the original stream management information file is madeup of (i) o_attribute( ) for storing attribution information about theentire original stream file managed by the original stream managementinformation file; (ii) video_unit_table( ) for storing information aboutthe VU; (iii) p_attribute( ) for storing attribution information aboutthe entire after-recording data file managed by the original streammanagement information file; and (iv) continuous_area_table( ) forstoring information about the CA.

As shown in FIG. 10( a), the video_unit_table( ) is made up of (i)number_of video_unit for indicating the number of the VUs; and (ii)video_unit_info( ) for storing information about each of the VUs.

As shown in FIG. 10( b), the video_unit_info( ) is made up of (i)VU_flags for indicating various kinds of attribution information about apredetermined VU; (ii) VU_PTS for storing a PTS (Presentation TimeStamp) of a top display frame of a predetermined VU; and (iii) VU_PN forindicating relative pack numbers counted from a top of the file. TheVU_PTS and the VU_PN make it possible to specify a position of a VUcorresponding to a specific PTS. Namely, the VU_PTS indicatesreproduction start time of the original stream (AV data).

As shown in FIG. 11( a), the VU_flags( ) includes first_unit_flag. Thefirst_unit_flag is 1-bit information. As shown in FIG. 11( b), thefirst_unit_flag indicative of 0b means that a managed VU is notpositioned in the head of the CU, whereas the first_unit_flag indicativeof 1b means that a managed VU is positioned in the head of the CU.

As shown in FIG. 12( a), the continuous_area_table( ) is made up of (i)number_of continuous_area for indicating the number of the CAs; and (ii)continuous_area_info( ) for storing information about each of the CAs.

As shown in FIG. 12( b), the continuous_area_info( ) is made up of (i)CA_flags for indicating various kinds of attribution information about apredetermined CA; (ii) CA_PTS for storing a PTS (Presentation TimeStamp) of a top display frame of a CU corresponding to the CA; and (iii)CA_PN for indicating relative pack numbers counted from a top of thefile. The CA_PTS and the CA_PN make it possible to specify a position ofa CA corresponding to a specific PTS in the original stream. The CA_PNindicates position information of a first continuous region forrecording the CA and the CU, in other words, the CA_PN indicates headposition information of the CA.

As shown in FIG. 13( a), the CA_flags( ) includes “placement_flag”. Theplacement_flag is 1-bit information. As shown in FIG. 13( b), theplacement_flag indicative of 0b means that a managed CA is notpositioned just before a corresponding CU (that is to be reproduced insynchronism with the CA), whereas the placement_flag indicative of 1bmeans that a managed CA is positioned just before a corresponding CU(that is to be reproduced in synchronism with the CA).

Making reference to the flag allows for realization whether or not thenon-destructively edited result possibly cause the interruption duringthe reproduction. Specifically, seeking of the CA is carried out whenthe placement_flag is indicative of 0b. This notifies that thereproduction is highly likely to be interrupted.

Note that explanation of the o_attribute( ) and the p_attribute( ) isomitted.

Finally explained is the program information file. As shown in FIG. 14,the program information file is made up of (i) pg_attribute( ) forstoring attribution information of entire program information; and (ii)scene_table( ) for storing information about scenes constituting theprogram.

As shown in FIG. 15( a), the scene_table( ) is made up of (i) number_ofscene for storing the number of the scenes; and (ii) scene_info( ) forstoring information about each of the scenes. As shown in FIG. 15( b),the scene_info( ) is made up of (i) sc_filename for storing a filenameof the original stream management information file that manages theoriginal stream file containing a predetermined scene; (ii) sc_start_PTSfor storing information indicating a position from which the scene isreproduced; and (iii) sc_duration for storing reproduction time of thescene.

<Processes During Recording>

The following explains processes performed in response to the user'sinstruction for picture recording, with reference to a flowchart of FIG.16. Note that an AV stream to be recorded on this occasion has a bitrate Ro of 12 Mbps, and has an audio bit rate Ra of 256 kbps, and issuch a stream that is in compliance with the constant VU reproductiontime method. Note also that, the following assumes that the managementinformation of the file system has already been in the RAM.

Firstly carried out is determination of a stream structure and astructure of the continuous region (S701). When each VU is constitutedby one GOP made up of 15 frames, substituted in Formula (6) and Formula(7) are the following conditions: Rs=20 Mbps, Ta=1 second, Rv=12 Mbps,Ra=256 kbps, and Tvmax=approximately 0.5 second. With this, Te(i) fallswithin a range from 3 seconds to 4 seconds. When Tvmax is approximately0.5 second, Te(i) satisfying this condition is 3 seconds. In this case,each CA is inserted in the AV stream for every 6 VUs.

A region size for the CA in this case is determined in consideration ofa pack header and a packet header, both of which are attached to theaudio data corresponding to 3 seconds. The above process in S701corresponds to a first step of dividing, according to the predeterminedinterval, the original stream serving as the AV data into the partial AVdata (CU, i.e., 6 VUs), and dividing, according to the predeterminedinterval, the after-recorded data serving as the associated data of theAV data into the partial associated data.

Then, a search is carried out for a vacant region capable of continuousstorage of the 6 VUs and one CA, with reference to the Space Bitmap inthe RAM 102. When no vacant region is found, the picture recording isstopped, and the user is notified that the recording cannot be carriedout (S702).

Next, the audio encoder 117 and the video encoder 118 are launched(S703). After that, a check is carried out whether or not datacorresponding to one ECC block (32 KB) or greater is accumulated in therecording buffer (S704). While the data is being accumulated, processesS705 to S708 are repeated.

Specifically, when data corresponding to one ECC block or greater isaccumulated in the recording buffer, a search in the disc is carried outfor a next vacant ECC block for storing the data, with reference to theSpace Bitmap in the RAM (S705). Carried out when vacancy is found is therecording, onto the disc, of the data that corresponds to one ECC blockand that is accumulated in the recording buffer 111 (S706). When novacancy is found, a search is carried out for a continuous vacant regionthat can store the nine VUs and the CA (S707). Then, the pickup is movedto the head of the vacant region found by the search (S708). Carried outafter that is the recording, onto the disc, of the data that correspondsto one ECC block and that is accumulated in the recording buffer 111(S706).

The process in S704 corresponds to a second step of securing a firstcontinuous region for continuously storing the partial AV data and thepartial associated data. Moreover, the process in S706 corresponds to athird step of continuously recording the partial AV data and the partialassociated data onto the first continuous region.

Meanwhile, when data accumulated in the recording buffer 111 is lessthan data corresponding to one ECC block, a check is carried out whetheror not an instruction for finishing the recording has been made (S709).When such an instruction has not been made, the sequence goes to S704.

On the other hand, when such an instruction has been made in S709, thefollowing processes are carried out. That is, dummy data is provided atan end of the data that is accumulated in the recording buffer and thatis less than 32 KB, so as to cause the accumulated data to have 32 KB(S710). Next, the data thus having 32 KB is recorded onto the disc (S711through S714). Note that processes in S711 through S714 are the same asthe processes in S705 through S708, respectively.

Carried out next is recording of (i) the management information aboutthe original stream onto the original stream management informationfile; and of (ii) the management information about the after-recordeddata, onto the after-recording data management information file (S715).Then, the file system management information is recorded onto theoptical disc 106 (S716). Note that the file system managementinformation thus recorded designates such that the CU and the CA arehandled as different files.

The process in S716 corresponds to a forth step of (i) recording, ontothe recording medium, the file system management information for (i)managing the partial AV data and the partial associated data asdifferent files, (ii) managing information for handling the partial AVdata and the partial associated data as files different from a file forsecuring the first continuous region.

The process in S715 corresponds to a fifth step of recording, onto therecording medium, (i) the reproduction start time of the partial AVdata, and (ii) the correspondence information of the partial AV data andthe partial associated data, both of which are disposed in the firstcontinuous region.

The following explains operations of the audio encoder 117, the videoencoder 118, and the multiplexer 113 during the processes. Resultsobtained by encoding carried out by these encoders are sent to the audiorecording buffer 119 and the video recording buffer 120, respectively.The multiplexer 113 multiplexes the respective sets of data into MPEG-2PS data, and then the MPEG-2 PS data is stored in the recording buffer114.

In cases where the recording buffer 114 receives a data corresponding toone VU and where the VU is 9×i-th VU (i is an integer equal to or largerthan 0), a CA having the aforesaid size is firstly sent to the recordingbuffer 111.

When the completion of the encoding of the data corresponding to the VUis notified to the host CPU 101, the host CPU 101 updates (i) themanagement information, in the RAM 102, about the original stream; and(ii) the management information, in the RAM 102, about theafter-recorded data. The update is carried out in accordance with thePTS at the head of the VU, the number of packs constituting the VU, andthe number of packs constituting the CA.

[Processes During Reproduction]

The following description explains processes when the user instructsreproduction of the program to which the after-recording was carriedout, with reference to a flowchart of FIG. 17. Note that the followingdescription assumes that the program information file used in thereproduction has already been in the RAM 102.

Firstly, carried out in reference to the sc_filename of the scene_info() in the program information file is opening of the original stream fileand the after-recording data file, each of which is referred by theprogram. Simultaneously, the original stream management information filemanaging these files is read out (S901).

Next, the scene number is set at 0 (S902). While the scene number issmaller than the number indicated by the number_of scene in thescene_table (S903), below-described reproduction of the scene is carriedout with reference to content of the scene_info corresponding to thescene number (S904). Upon completion of the reproduction of the scene,numeral 1 is added to the scene number (S905).

Next, processes of reproducing the scene will be explained withreference to FIG. 18. Firstly carried out is a search forvideo_unit_info( ) having the largest VU_PTS that is equal to or smallerthan the sc_start_PTS (S801), in reference to the video_unit_table( ) ofthe original management information in the RAM 102. The process in S801is carried out to find a VU number of the scene from which thereproduction starts. Note that the VU number represents order of sets ofthe video_unit_info( ) of the video_unit_table( ).

Carried out next is a search for continuous_area_info( ) having thelargest CA_PTS that is equal to or smaller than sc_start_PTS (S802), inreference to the continuous_area_table( ). The process in S802 iscarried out to find an address of the CA corresponding to the scene fromwhich the reproduction starts. Thereafter, packs are read out from theafter-recording data file, those packs falling within a range from (i) apack specified by a CA_PN in the continuous_area_info( ), to (ii) a packjust before a pack specified by a CA_PN in a next continuous_area_info(S803).

Next, an address of the VU is found in reference to the VU_PN of thevideo_unit_info( ) which corresponds to the present VU number (S804).Based on the address, the VU is read out from the original stream file(S805). Carried out next is judgment whether or not the scene is over(S806). Specifically, when elapsed reproduction time of the presentscene is equal to or exceeds the time specified by the sc_duration ofthe scene_info( ), the scene is judged to be over.

In cases where the reproduction of the scene is not over, numeral 1 isadded to the VU number (S807). Then, carried out is judgment whether ornot the VU managed by the video_unit_info( ) is positioned in the headof the CU, by referring to the first_unit_flag of the video_unit_info( )(S808).

When the first_unit_flag is indicative of 1, the VU managed by thevideo_unit_info( ) is judged to be positioned in the head of the CU, andthe address of the CA is found by performing the aforementioned step(S809). Thereafter, the CA is read out from the after-recording file(S810). On the contrary, when the first_unit_flag is indicative of 0,the VU managed by the video_unit_info( ) is judged to be positioned notin the head of the CU, and the processes from S804 to S808 are repeated.

During the readout of the stream and the data from the optical disc 106,the decoding processes are carried out as follows. The readout VU issent to the de-multiplexer 112, and the de-multiplexer 112 extracts avideo PES packet and an audio PES packet from the VU. The video PESpacket is sent to the video reproduction buffer 111, and the audio PESpacket is sent to the audio reproduction buffer 110.

The de-multiplexer 112 extracts a SCR from the pack header, and updatesthe system clock 105. The video decoder 116 and the audio decoder 115carry out decoding and outputting at the moment when the system clock105 coincides with a time stamp attached to the PES packet header.

In Embodiment 1, each CU storing the original stream is physicallyadjacent, in the disc, to each CA storing the after-recorded data to bereproduced in synchronism with the CU. For this reason, even when thescene starts from a VU positioned in the vicinity of a terminal of theCU, the seeking of the VU by moving the pickup from the position of theCA requires only a little suspension time during the data readout.

On the contrary, in the case where the after-recorded data is notpositioned adjacent to the original stream to be reproduced insynchronism, the seeking time between (i) the readout of theafter-recorded data in the head portion of the scene and (ii) thereadout of the original stream corresponds to, at worst, such time thatthe pickup moves from the innermost side of the disc to the outermostside of the disc. Accordingly, the reproduction in this case is highlylikely to be interrupted between the scenes as compared with the presentembodiment.

[Processes During after-Recording]

The following explains processes carried out in response to the user'sinstruction to perform the after-recording. The processes during theafter-recording are carried out by performing several processes inaddition to the aforementioned reproduction processes. For this reason,explanation here is made only for those differences from theabove-described processes.

Firstly, for the recording of the after-recorded data, the audio encoder117 is launched concurrently with a reproduction start of the scene. Aresult obtained by encoding the after-recorded data is sent to the audiorecording buffer 119 in the form of a PES packet. The multiplexer 113packs and sends the PES packet to the recording buffer 114 such that theSCR of a pack header and the PTS in a packet header are caused to bematched with those in the original stream, respectively.

At the moment when the recording buffer 114 receives a pack having a PTSexceeding a range of the CU that is being decoded, a pack row in therecording buffer 114 is recorded onto the after-recorded data file. Theposition of the CA to be recorded is found in accordance with the PTS ofthe CU presently being decoded, with reference to thecontinuous_area_table( ).

In cases where defect occurs during the recording of the CA, the CA thatis being recorded is discarded, and the CA is newly recorded ontoanother region. A reason for this is that: the defect causes a decreasein a recording region for the CA being recorded, so that the region forthe CA can no longer store data corresponding to reproduction time ofthe relevant CU. In this case, the placement_flag in thecontinuous_area_info( ) managing the CA is changed to 0 so as toindicate that the CA does not exist before the relevant CU. Also, in thefile system management information, an extent of the discarded CA isreplaced with an extent of the newly made CA.

This makes it possible to recognize in which part the CA and the CU arenot continuously recorded, by merely referring to the placement_flagduring the non-destructive editing and the reproduction of thenon-destructively edited result. On this account, the user can benotified in advance that reproduction will be highly likely to beinterrupted during reproduction of the aforesaid part. Further, the flagcan be used in future for re-positioning the CA and the CU, which arenot continuously recorded, to be continuously recorded.

Modified Example of Embodiment 1

In Embodiment 1, data is recorded onto the after-recording data file, inaccordance with the MPEG-2 format, as is the case with the originalstream file; however, data may be recorded onto the after-recording datafile, in compliance with the Elementary Stream in which recording doesnot utilize such packing and packeting. This cuts out the need of there-packing after extracting an AAU from a pack and replacing theextracted AAU, when overwriting a part of the after-recorded data of theCA.

Further, in Embodiment 1, the CA stores the audio data, but may storedifferent types of data such as graphics data to be superimposed on thevideo in the original stream.

In Embodiment 1, one AAU can be recorded over a plurality of packs, butmay be stored in one pack. With this, a part of the after-recorded datain the CA can be rewritten merely by overwriting a pack containing arelevant AAU.

In Embodiment 1, when occurrence of the defect in the CA is detectedduring the after-recording, the CA is discarded and the after-recordeddata is recorded in another region. However, when (i) the occurrence ofthe defect has been assumed and (ii) the size of the CA is determined,upon initial picture recording, in consideration of margin for suchdefect, and (iii) such defect is detected, the after-recorded data maybe recorded onto a position coming after the position at which thedefect occurred, in the CA. This allows continuous recording of the CAand the CU.

For correlation (correspondence) between the CA and the CU that arehandled as different files, the respective head addresses of the CU andthe CA can be found in accordance with the time stamp of the head of thedata in the CU. However, any way of ensuring the correlation may beused.

Embodiment 1 uses the MPEG-2 PS; however, similar effect can be obtainedby using the MPEG-2 TS.

Embodiment 2

Embodiment 2 of the present invention will be explained with referenceto FIG. 19.

Differences between Embodiment 1 and Embodiment 2 are as follows. Thatis, in Embodiment 1, a plurality of sets of data to be synchronouslyreproduced are continuously disposed in the recording medium, and thesesets of data are managed as different files. In contrast, in Embodiment2, the data sets are in the same reproduction time-line, but are notsimultaneously reproduced. In Embodiment 2, reproduction is carried outby switching the data sets between each other.

Specifically, Embodiment 2 utilizes the multi-angle function in theDVD-Video, i.e., a function for switching images viewed from a pluralityof angles in the same time-line.

Note that a recording operation according to Embodiment 2 issubstantially the same as that of Embodiment 1, i.e., the relationbetween the original stream and the after-recorded data that should besynchronously reproduced in Embodiment 1 is merely replaced with therelation between two types of the original streams that are in the sametime-line in Embodiment 2.

<File Structure>

The video/audio data are multiplexed in compliance with the MPEG-2 PSstandard, and are recorded onto different files in accordance withangles. In an example shown in FIG. 19( a), first angle data is recordedonto ANGL0001.M2P, and second angle data is recorded onto ANGL0002.M2P.

<Layout in the Disc>

As shown in FIG. 19( b), the first angle data ANGL0001.M2P is dividedinto partial data 2021, 2022, and 2023. Likewise, the second angle dataANGL0002.M2P is divided into partial data 2011, 2012, and 2013. Thesesets of the partial data obtained by dividing ANGL0001.M2P andANGL0002.M2P are alternately positioned in a disc 2001. A method fordetermining a dividing scale is similar to a method for positioningmulti-angle data in case of the DVD-Video, so that explanation thereofis omitted here.

This allows realization of angle switching response as fast as themulti-angle switching response in the DVD-Video, and allows each of thedata files to be reproduced by a general MPEG-2 PS compatible decoder.

Embodiment 3

Embodiment 3 of the present invention will be described with referenceto FIG. 21 through FIG. 28.

A difference between Embodiment 3 and Embodiment 1 is as follows. Thatis, in Embodiment 1, the after-recording region is managed by a singlefile (i.e., by the after-recording data file (SHRP0001.PRE; see FIG.4)). In contrast, in Embodiment 3, the file for securing a vacant regionis made separately from the file for storing each set of AV data. Notethat Embodiment 3 is similar to Embodiment 1, so that explanation hereis focused on a difference therebetween.

<File/Directory Structure>

FIG. 21 illustrates a file/directory structure of Embodiment 3. Thefile/directory structure is obtained by adding, to the file/directorystructure (see FIG. 4) in Embodiment 1, (i) an after-recording regionreservation file (SHRP0001.RSV), (ii) an after-recording data managementinformation file (SHRP0001.PMI), and (iii) a graphics file(SHRP0001.PNG).

The after-recording region reservation file (SHRP0001.RSV) is a file forreserving an after-recording region. The after-recording data managementinformation file (SHRP0001.PMI) is management information correspondingto the after-recording data file. The graphics file (SHRP0001.PNG) is afile for storing graphics data superimposed on video. Note that aprogram information file (SHRP0001.PMG), an original stream managementinformation file (SHRP0001.OM1), and an original stream file(SHRP0001.M2P) are the same as those in Embodiment 1, respectively.

The after-recording region reservation file is made per original streamfile, and recording is carried out thereonto during picture recording.The after-recording data management information file is made perafter-recording data file. The graphics file is a file added when thenon-destructive editing is carried out after the picture recording, andis a file for storing images to be superimposed on the video. Examplesof the images include titles and handwritten letters (characters). Suchimages are stored in compliance with the PNG (Portable NetworkGraphics).

The after-recording data file (SHR0001.PRE) is not generated until theafter-recording is carried out, unlike Embodiment 1. In other words,during the picture recording, the after-recording region reservationfile is recorded, in place of the after-recording data file as inEmbodiment 1.

<Structure of an AV Stream>

A structure of an AV stream is the same as the structure of the AVstream, explained above with reference to FIG. 5, in Embodiment 1.

<After-Recording Region Reservation File>

The after-recording region reservation file has the same structure asthe after-recording data file (see FIG. 6) in Embodiment 1. That is, theafter-recording region reservation file is constituted by the integralnumber of continuous areas (CAs). Each CA corresponds to one CU in theoriginal stream file, and secures a region for storing after-recordeddata corresponding to a relevant CU. Note that the CA here is merely inuse for securing the region, and is not AV data to be reproduced. Forthis reason, the CA may contain any kinds of data.

<Layout in the Disc>

The following explains how data in the files of Embodiment 3 arepositioned in the disc. FIGS. 22( a) and 22(b) illustrate respectivepositions of the data of the files in cases where no after-recording iscarried out after the picture recording (in other words, cases where theafter-recording data file is not made.) The original stream file(SHRP0001.M2P) and the after-recording region reservation file(SHRP0001.RSV) correspond to each other, and the CUs of the originalstream file (SHRP0001.M2P) and the CAs of the after-recording regionreservation file (SHRP0001.RSV) are recorded onto the optical disc 106such that the CAs respectively come just before the corresponding CUs(see FIG. 22( b)).

The following explains respective positions of the data of the filesincluding the after-recording region reservation file, theafter-recording data file, and the graphics file, i.e., positions of thedata of these files after addition of audio and graphics, with referenceto FIGS. 23( a) and 23(b). FIG. 23( a) illustrates respective structuresof the graphics file (SHRP0001.PNG) and the after-recording data file(SHRP0001.PRE), each of which is additionally recorded onto the disc.The graphics file stores graphics data IMG. The after-recording datafile stores after-recorded audio data PR#1, PR#2, and PR#3 whichrespectively correspond to CU#n−1, CU#n, CU#n+1 in the original streamfile shown in FIG. 22( a).

The IMG and the PRs are positioned in the optical disc 106 as shown inFIG. 23( b). Specifically, in FIG. 22( b), the PR#1 is positioned withina region secured by the CA#n−1, the PR#2 is positioned within a regionsecured by the CA#n, and the PR#3 is positioned within a region securedby the CA#n+1. The graphics data IMG is positioned within a regionsecured by the CA#n+1.

Such Positioning of the IMG and the PRs within the respective regionssecured by the CAs causes reduction of respective region sizes of theCA#n−1, the CA#n, and the CA#n+1. The reduction is realized by changingextents in the file system management information, these extentsmanaging the respective regions of the CAs.

Thus, such various types of data can be added with ease after thepicture recording, by introducing the after-recording region reservationfile for managing vacancy in the after-recording regions. Further, thegraphics data and the after-recording audio data are stored in thedifferent files, so that a different program can refer merely to thegraphics data. This allows more flexibility.

<Formats Of Management Information Files>

A format of the original stream management information file is the sameas that of the original stream management information file in Embodiment1, so that explanation thereof is omitted here. A format of theafter-recording data management information file is almost the same asthat of the original stream management information file in Embodiment 1,but p_attribute( ) and the continuous_area_table( ) are not in theoriginal stream management information file unlike in Embodiment 1.

Next, FIG. 24 illustrates a structure of a program information file. Theprogram information file according to Embodiment 3 includes: (i)subaudio_table( ) for managing the audio data added after the picturerecording; and (ii) graphics_table( ) for managing the graphics dataadded after the picture recording, unlike the program information file(see FIG. 14) according to Embodiment 1.

As shown in FIG. 25( a), the subaudio_table( ) is made up of (i)number_of_subaudio for indicating the number of sets of the audio data;and (ii) subaudio_info( ) for storing information about the respectivesets of the audio data. As shown in FIG. 25( b), the subaudio_info( ) ismade up of (i) SA_filename for storing a filename of the after-recordingdata management information file used for managing predetermined audiodata; (ii) SA_flags for managing various attributions of predeterminedaudio data; (iii) SA_start_time for indicating reproduction start timingof the audio data in the program; and (iv) SA_duration for indicatingreproduction duration time of the audio data in the program.

On the other hand, as shown in FIG. 26( a), the graphics_table( ) ismade up of (i) number_of graphics for indicating the number of graphicsfiles; and (ii) graphics_info( ) for storing information about each ofthe graphic files. As shown in FIG. 26( b), the graphics_info( ) is madeup of (i) gr_filename for storing a filename of a predetermined graphicsfile; (ii) gr_flags for managing various attributions of predeterminedgraphics data; (iii) gr_start_time for indicating reproduction starttiming of the graphic data in the program; and (iv) gr_duration forindicating reproduction duration time of the graphic data in theprogram.

The SA_flags and the gr_flags have an identical structure, and each ofthem includes a flag termed “interleave_flag” as shown in FIG. 27( a).The interleave_flag is 1-bit information. See FIG. 27( b). When theinterleave_flag is indicative of 0b, managed audio data or a managedgraphics file does not come just before a relevant CU (that is to bereproduced in synchronism with the audio data or the graphics file). Incontrast, when the interleave_flag is indicative of 1b, the managedaudio data or the manage graphics file comes just before the relevant CU(that is to be reproduced in synchronism with the audio data or thegraphics file). Reference to the flag allows realization whether or notreproduction of a non-destructive edited result possibly causesinterruption in the reproduction. In other words, when the flag isindicative of 0b, the seeking of a CA is carried out, so that thereproduction is highly likely to be interrupted.

<A Method for Determining a CU Scale>

A method for determining a CU scale is the same as the method explainedwith reference to FIG. 7 and FIG. 8 in Embodiment 1.

<Processes During Recording>

Processes during recording are the same as the processes explained withreference to FIG. 16 in Embodiment 1.

<Processes During Reproduction>

The following explains processes performed in response to user'sinstruction for reproduction of the program having already beensubjected to the after-recording. Flow of the processes is essentiallythe same as the flow explained with reference to the flowchart of FIG.17 in Embodiment 1, so that explanation for the same processes explainedabove is omitted here. A difference between the reproduction processesaccording to Embodiment 3 and those according to Embodiment 1 lies inprocesses of reproducing the scenes. For this reason, the followingexplanation addresses the scene reproduction processes with reference toFIG. 28.

Firstly carried out is a search for video_unit_info( ) having thelargest VU_PTS that is equal to or smaller than the sc_start_PTS (S801),in reference to the video_unit_table( ) of the original managementinformation in the RAM 102. Note that order of sets of thevideo_unit_info( ) in the video_unit_table( ) is represented by VUnumbers.

Next, a search is carried out for checking presence of a graphic fileand audio data, each of which is to be reproduced in synchronism with aCU including a present VU (S802′). The search is carried out withreference to the graphics_table( ) and the subaudio_table( ) of theprogram information file. When such a graphics file and such audio dataexist, the graphics file is read out, and corresponding audio data isread out in reference to the audio data management information filemanaging the audio data (S803′).

Next, an address of the VU is found with reference to the VU_PN of thevideo_unit_info( ) which corresponds to the present VU number (S804).Based on the address, the VU is read out from the original stream file(S805). Carried out next is judgment whether or not the scene is over(S806). Specifically, when elapsed reproduction time of the presentscene is equal to or exceeds the time specified by the sc_duration ofthe sceneinfo( ) the scene is judged to be over.

When the reproduction of the scene is not over, numeral 1 is added tothe VU number (S807), and reference is made to the first_unit_flag inthe video_unit_info. In cases where the first_unit_flag is indicative of1, the VU managed by the video_unit_info( ) is positioned in the head ofthe CU (S808). Then, the check is carried out, in accordance with theaforementioned steps, for presence of the graphics file and the audiodata which are to be used for the synchronized reproduction (S809′).When such a graphics file and such audio data are found, they are readout in accordance with the aforementioned steps (S810′).

<Processes During the after-Recording>

The following explains processes performed in response to user'sinstruction for the after-recording. The processes during theafter-recording are performed by performing several processes inaddition to the aforesaid reproduction processes. For this reason, theexplanation here addresses only a difference therebetween.

Firstly, presence of after-recording regions (regions for theafter-recording) in the recording medium is checked. Specifically, thecheck is carried out with respect to the continuous_area_info of themanagement information file about the stream that is to beafter-recorded, in order to find whether or not each region secured bythe after-recording region reservation file has a size capable ofstoring the after-recorded data. When the size of the region issufficient, the after-recorded data is recorded onto the region. Whenthe size of the region is insufficient, the after-recorded data isrecorded onto a region other than the region secured by theafter-recording region reservation file.

Next, the audio encoder 117 is launched concurrently with start ofreproduction. An encoded result of the after-recorded data is sent tothe audio recording buffer 119, in the form of PES packets. Themultiplexer 113 packs and sends the PES packets to the recording buffer114 such that a SCR of a pack header and a PTS in a packet headercorrespond to those in the original stream, respectively.

At the moment when the recording buffer 114 receives a pack having a PTSexceeding a range of a CU that is presently being decoded, the pack rowin the recording buffer 114 is recorded onto the after-recording datafile. A position of the CA to be recorded is found in accordance withthe PTS of the CU presently being decoded, with reference to thecontinuous_area_table( ). The after-recorded data recorded onto theafter-recording data file is recorded onto the region secured by the CA.

At the moment of completion of the after-recording, the followings arecarried out. Firstly carried out is creation of the after-recording datamanagement file which corresponds to the after-recording data file thusrecorded. Upon the creation of the after-recording data management file,a set of video_unit_info( ) is made per CU.

Next, an entry is added to the subaudio_table of the program informationfile. In cases where the after-recorded data is recorded onto the regionsecured by the after-recording region reservation file, theinterleave_flag of the SA_flags( ) is set at 1 upon the addition of theentry. In contrast, in cases where the after-recorded data is notrecorded onto the region, the interleave_flag is set at 0 thereupon.

Further, the region storing the after-recorded data is ruled out ofscope of the file management of the after-recording region reservationfile. In other words, the size of the after-recording region reservationfile is reduced. Moreover, a CA_PN corresponding to each entry in thecontinuous_area_table( ) is reduced by the reduced size. With this,reference to the continuous_area_info( ) allows recognition of remaineddata storage space in each CA.

<Processes During Addition of the Graphics Data>

The following explains processes performed in response to user'sinstruction for adding, to the video, the graphics data that is to besuperimposed on the video. Firstly, presence of a region for storing thefile containing the graphics data is checked. Specifically, a check iscarried out with respect to the continuous_area_info( ) in themanagement information file about the stream to which the graphics datais to be added, and a check is carried out for presence of a region forstoring the graphics data in a CA corresponding to a CU containing avideo frame from which the graphic data to be superimposed starts to bedisplayed.

When the graphics data can be recorded onto the CA, the graphics data isrecorded onto the region. As is the case with the completion of theafter-recording, the region storing the graphics data is ruled out ofthe scope of the management by the after-recording region reservationfile. CA_PNs of entries of CAs coming after the CA are reduced by thereduced size. Moreover, one entry of the graphics_info( ) is added tothe graphics_table( ) of the program information file, and theinterleave_flag of the gr_flags( ) in the entry is set at 1. In thiscase, the graphics data is so recorded onto the disc as to be positionedadjacent to the video data to be reproduced together. With this, noseeking is required for readout of the graphics data upon the videoreproduction. This restrains the interruption of the video reproductiondue to the seeking, and reduces power consumption.

In contrast, when the graphics data cannot be recorded in the CA, thegraphics data is recorded onto another region. One entry of thegraphicsinfo( ) is added to the graphics_table( ) of the programinformation file, and the interleave_flag of the gr_flags( ) in theentry is set at 0. By referring to the flag during the reproduction, itis possible to notify, before the video reproduction, the user that thevideo reproduction is possibly interrupted.

Modified Example of Embodiment 3

In Embodiment 3, the graphics file and the after-recording data file isadditionally recorded after the picture recording; however, the filesmay be recorded during the picture recording. Also in this case, thegraphics file and the after-recording data file can be handled asindependent files from the video file. Moreover, the video file is ageneral MPEG-2 PS file, and the seeking is not required for thesynchronized reproduction.

In Embodiment 3, the graphics file is in compliance with the PNG format,but may be in compliance with other file formats such as the JPEG.

Embodiment 4

Embodiment 4 of the present invention will be explained with referenceto FIG. 29 and FIG. 30. Embodiment 4 is the same as Embodiment 1 exceptthe positioning of the data (file) in the disc and the method fordetermining the CU scale. In other words, Embodiment 4 providesvariations of the positioning and the method of Embodiment 1. For thisreason, the following explanation addresses the differences.

<File/Directory Structure>

A file/directory structure in Embodiment 4 is the same as that inEmbodiment 1, so that explanation thereof is omitted.

<Structure of AV Stream>

A difference between a structure of an AV stream in Embodiment 4 andthat in Embodiment 1 lies in only that: the CUs may not be continuouslyrecorded in the present embodiment.

<After-Recording Data File>

An after-recording data file in Embodiment 4 is the same as that inEmbodiment 1, so that explanation thereof is omitted.

<Layout in the Disc>

The following explains how respective data of an original stream fileand an after-recording data file are positioned in the disc, withreference to FIG. 29. FIG. 29( a) illustrates the original stream file(SHRP0001.M2P) and the after-recording data file (SHRP0001.PRE) whichcorrespond to each other. Essentially, the respective data of theoriginal stream file and the after-recording data file are recorded ontothe optical disc 106 such that a CA comes just before a correspondingCU, like in Embodiment 1. However, the CU may be divided, unlikeEmbodiment 1. FIG. 29( b) illustrates an example in which a CU#n−1 and aCU#n are provided. However, it should be noted that the CA must not bedivided. Note also that a total of reproduction time of VUs in onecontinuous region must be equal to or longer than reproduction time ofthe CU.

Such division of the CU allows a vacant region to be effectively used.For example, see a case where CUs each corresponding to 16 seconds arerespectively recorded onto continuous vacant regions that are in theoptical disc 106 and that correspond to 20 seconds in total. In caseswhere each CU is not divided, the vacant regions used for the recordingcorrespond to only 16 seconds, and the remaining corresponding to 4seconds is left unused. On the contrary, in cases where the CU isdivided, the vacant regions corresponding to 20 seconds can be fullyused.

<A Method for Determining a CU Scale>

The following explains a method for determining reproduction time of aCU, with reference to FIG. 30. As is the case with Embodiment 1, in themethod, the reproduction time of the CU is determined such that theseamless reproduction does not fail when the after-recording is carriedout with the use of (i) a device (reference device model) set as areference for ensuring compatibility between devices; and (ii) anafter-recording algorism (reference after-recording algorism) set as areference therefor.

The reference device model is the same as that of Embodiment 1, so thatexplanation thereof is omitted.

The reference after-recording algorism can be described as follows:

(a) Essentially, upon completion of readout of a present CU, recordingof a CA is carried out.

(b) In cases where an end of a CU coming after the presently-readout CUis stored in a different continuous region, recording of the CA ispostponed until readout of the subsequent CU is over.

FIGS. 30( a) and 30(b) illustrate examples of the referenceafter-recording algorism. FIG. 30( a) illustrates an example of theabove operation (a). Note that the numbers (1) through (8) in FIG. 30respectively correspond to the following numbers (1) through (8).

(1) Read out an n-th CU termed “CU#N”. (2) Move the pickup to a CA#Mthat should be recorded next, upon completion of encoding ofafter-recorded data corresponding to the CA#M. (3) Record theafter-recorded data onto the CA#M. (4) Move the pickup to a CU#N+1. (5)Read out the CU#N+1. (6) Move the pickup to a CA#M+1 that should berecorded next, upon completion of encoding of after-recorded datacorresponding to the CA#M+1. (7) Record the after-recorded data onto theCA#M. (8) Move the pickup to a CU#N+2.

See the case of FIG. 30( b) illustrating an example of the aboveoperation (b): (1) Read out the CU#N, but skip the recording of the CAimmediately after the readout of the CU#N, and then read out a formerportion of a CU#N+1 coming after the CN#N. This is because the CU#N andthe former portion of the CU#N+1 are positioned in the same continuousregion, and because an end of the CU#N+1 is positioned in a differentcontinuous region. (2) Move the pickup to a CA#M upon completion ofreading out the CU#N+1 until the end of the continuous region. (3)Record the after-recorded data onto the CA#M. (4) Move the pickup to alatter portion of the CU#N+1.

With such an algorism, a jump between the continuous regions and a jumpfor the recording of the CA can be carried out at a time even in thecase where the CU is divided. This minimizes the interruption of thedata readout due to such jumps, with the result that each continuousregion can have a smaller length and each CU and each CA have smallerscales. On this account, the vacant regions in the disc can beeffectively used.

In the case where the after-recording is carried out with the use of theaforesaid reference device model and the aforesaid referenceafter-recording, the after-recording buffer 504 is surely free from theoverflow, and the track buffer 502 is surely free from the underflow, aslong as the following condition is satisfied.

That is, the condition is satisfaction of Formula (1) described inEmbodiment 1. Note that symbols in Embodiment 4 have the same meaningsas the symbols in Embodiment 1, respectively, as long as specificexplanation of such symbols is not made.

As is the case with Embodiment 1, Tw(i) in Formula (1) is represented byFormula (4). However, Tr(i) therein is represented by the followingFormula (8):

Tr(i)=Te(i)×Ro/Rs+Te(i)×Ra/Rs  (8)

Formula (8) is a formula obtained by removing, from Formula (3), Taindicating the jump.

A reason for removing Ta indicating the jump is as follows. That is, inEmbodiment 4, the jump during the readout of the CU is carried out atthe time of recording the CA, so that the jump during the readout of theCU is regarded as the jump during the recording of the CA. This allowsreduction of respective scales that the CU and the continuous regionfinally have.

When Formula (8) and Formula (4) are substituted in Formula (1) to solvefor Te(i), a condition of Te(i) ensuring the real-time after-recordingis obtained as the following Formula (9):

$\begin{matrix}{{{{Te}(i)} \geqq \frac{2{Ta} \times {Rs}}{{Rs} - {Ro} - {2{Ra}}}}{\text{?}\text{indicates text missing or illegible when filed}}} & \text{?}\end{matrix}$

Accordingly, the CU reproduction time lower limit value Temin thatensures the after-recording is represented by the following formula(10):

$\begin{matrix}{{{{Te}\mspace{14mu} \min} = \frac{2{Ta} \times {Rs}}{{Rs} - {Ro} - {2{Ra}}}}{\text{?}\text{indicates text missing or illegible when filed}}} & \text{?}\end{matrix}$

A CU reproduction time upper limit value Temax is so set as to satisfythe following Formula (11):

$\begin{matrix}{{{{Te}\mspace{14mu} \max} = {\frac{2{Ta} \times {Rs}}{{Rs} - {Ro} - {2{Ra}}} + {{Tv}\mspace{14mu} \max}}}{\text{?}\text{indicates text missing or illegible when filed}}} & \left( {1\text{?}} \right.\end{matrix}$

where Tvmax indicates maximum reproduction time of the VU.

The setting of the upper limitation value of the CU reproduction time iscarried out so as to allow for estimation of maximum retardation memoryamount required for the synchronized reproduction of the after-recordedaudio and the normal audio, and so as to ensure reproductioncompatibility. Note that, in Embodiment 4, the multiplexing intervallower limit value Temin is set according to the audio bit rate Ra andthe video bit rate Rv; however, the lower limit value may be constant atany value as long as the lower limit value is based on the maximum bitrate.

Moreover, reproduction time of the VU in the stream may be constant orvariable as long as the reproduction time of the CU is in accordancewith the aforementioned restriction.

<Required Buffer Memory Amount>

In the present embodiment, a volume required, during theafter-recording, in the track buffer 502 is determined based on thefollowing idea. That is, in Embodiment 4, the largest volume is requiredin cases where the recording of the after-recorded data is seriallycarried out onto the CAs. Specifically, the largest volume is requiredin cases where each of the CUs is divided in a portion just before anend of the CU. In other words, the largest volume is required in caseswhere the CU is separately stored in two continuous regions, and wheremost data in the CU is stored in a former one of the continuous regions.

In this case, according to the aforesaid reference after-recordingalgorism, the after-recording is carried out in the following manner.That is, the readout of the CU continues until a portion just before theend of the CU, and then the pickup moves to the CA so as to record theafter-recorded data. Then, the pickup moves back so as to read out theslight amount of the remained data in the CU. Immediately after thereadout, the pickup moves to the next CA to record the after-recordeddata, and moves back to read out the CA. Such an operation requires avolume that allows for reproduction continuously lasting over a periodcorresponding to (i) two recording operations of the after-recordingdata with respect to the CAs; and (ii) the readout operation of one CA.A specific way of securing such a volume Bpb of the track buffer memory502 is to be in accordance with the following Formula (12):

Bpb=(2×(2×Ta+Temax×Ra/Rs)+Temax×Ra/Rs)×Ro  (12)

<Formats of the Management Information Files>

Formats of the management information files in Embodiment 4 are the sameas those in Embodiment 1, respectively, so that explanation thereof isomitted here.

<Processes During Recording>

Processes during recording in Embodiment 4 are the same as those inEmbodiment 1, except that Embodiment 4 is free from the restriction incontinuously recording the CUs onto the disc.

<Processes During Reproduction>

Processes during reproduction in Embodiment 1 are the same as those inEmbodiment 4, so that explanation thereof is omitted here.

<Processes During after-Recording>

Processes during after-recording in Embodiment 4 are the same as thosein Embodiment 1, except that the algorism shown in FIG. 30 is utilizedduring the after-recording. For this reason, explanation thereof isomitted here.

Modified example of Embodiment 4

Embodiment 4 is explained as a variation of Embodiment 1; however,Embodiment 4 is applicable to (i) a case where the after-recordingregion reservation file is used as in Embodiment 3, and (ii) a casewhere one file deals with the stream data and the after-recorded data asin Japanese Laid-Open Patent Publication Tokukai 2001-43616. In otherwords, essence of the invention disclosed by the present embodiment liesin (i) the respective physical positioning of the after-recording regionand the initially recorded video data; and (ii) the model setting forsetting the parameters for the positioning.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a digital recording/reproducingapparatus (video disc recorder) that has an after-recording function andthat uses disc (disk) recording medium such as a DVD and a hard disk.

1-14. (canceled)
 15. An AV data reproducing device for reproducing AV data stored on a recording medium storing at least AV data and associated data which is associated with the AV data, the AV data and the associated data constituting a scene to be reproduced at the same time, wherein: the AV data and the associated data are so stored on the recording medium that the AV data is divided into partial AV data in accordance with a predetermined rule, the associated data is divided into partial associated data in accordance with a predetermined rule, and the partial AV data and the partial associated data, which are to be reproduced at the same time, are disposed alternately; the recording medium further storing: file system management information for managing information for handling as different files the AV data and the associated data; the file system management information includes: position information of the partial AV data in an order of reproducing the partial AV data, and position information of the partial associated data in an order of reproducing the partial associated data; the device comprising: a section for acquiring the file system management information from the recording medium.
 16. The AV data reproducing device as set forth in claim 15, wherein each of the AV data and the associated data is multiplexed in accordance with a predetermined multiplexing rule.
 17. An AV data reproducing method for reproducing AV data stored on a recording medium storing at least AV data and associated data which is associated with the AV data, the AV data and the associated data constituting a scene to be reproduced at the same time, wherein: the AV data and the associated data are so stored on the recording medium that the AV data is divided into partial AV data in accordance with a predetermined rule, the associated data is divided into partial associated data in accordance with a predetermined rule, and the partial AV data and the partial associated data, which are to be reproduced at the same time, are disposed alternately; the recording medium further storing: file system management information for managing information for handling as different files the AV data and the associated data; the file system management information includes: position information of the partial AV data in an order of reproducing the partial AV data, and position information of the partial associated data in an order of reproducing the partial associated data; the method comprising: a step of acquiring the file system management information from the recording medium.
 18. A non-transitory computer readable recording medium for storing a program for causing a computer to reproduce AV data stored on a recording medium storing at least AV data and associated data which is associated with the AV data, the AV data and the associated data constituting a scene to be reproduced at the same time, wherein: the AV data and the associated data are so stored on the recording medium that the AV data is divided into partial AV data in accordance with a predetermined rule, the associated data is divided into partial associated data in accordance with a predetermined rule, and the partial AV data and the partial associated data, which are to be reproduced at the same time, are disposed alternately; the recording medium further storing: file system management information for managing information for handling as different files the AV data and the associated data; the file system management information includes: position information of the partial AV data in an order of reproducing the partial AV data, and position information of the partial associated data in an order of reproducing the partial associated data; the program causing the computer to perform: a step of acquiring the file system management information from the recording medium.
 19. A non-transitory recording medium for use by the AV data reproducing device according to claim 15, the recording medium storing the AV data, the associated data, and the file system management information so that the AV data, the associated data, and the file system management information are capable of being supplied to the AV data reproducing device. 